Control system



Aug-18,1941 A. E. ANDERSON 2,293,154

CONTROL SYSTEM I Filed June 27, 1940 Inventor; Arvicl E. Anderson,

'* b fla 9 His Atto neg.

Patented Aug. 18, 1942 CONTROL SYSTEM Arvid E. Anderson, Drexel Hill, Pa., assignor to General Electric Company, a corporation of New York Application June 27, 1940, Serial No. 342,763

6 Claims.

My invention relates to control systems and particularly to systems for controlling the connections between an electric circuit and a plurality of reactance devices, such as capacitors, so as to improve the power-factor and the voltage of the circuit.

In order to prevent wide variations in the electric condition of the circuit, such as the voltage, which it is desired to maintain constant, it is necessary that the changes inthe amount of reactance connected to the' circuit be relatively small. Also it is desirable to keep to a minimum the amount of switching apparatus required to sheet the desired reactance changes in order to keep the cost of such switching apparatus as low as possible.

One object of my invention is to provide an improved arrangement of apparatus for controlling the connections between an electric circuit and a plurality of reactance devices whereby desired equal changes in the amount of reactance connected to the circuit can be eiiected with the minimum amount of switching apparatus.

In accordance with my invention, I provide a plurality of reactance devices respectively having reactances, which differ in an arithmetical progression, the smallest reactance being equal to the minimum change it is desired to effect in the amount of reactance connected to the circuit. An individual switch is provided for connecting each reactance device to the electric circuit, and suitable means are provided for selectively operating the various switches so that the amount of reactance connected to the circuit is progressively varied automatically in equal increments until the desired electric condition of the circuit is obtained.

My invention will be better understood from the following description when taken in connection with the accompanying drawing the single figure of which diagrammatically illustrates a capacitor control system embodying my invention, and its scope will be pointed out in the appended claims.

Referring to the accompanying drawing, I, 2 and 3 represent capacitors respectively having capacities which differ in an arithmetical progression. For example, capacitor 1 has a capacity equal to the minimum change it is desired to effect in the amount of capacity connected to circuit 4; capacitor 2 has a capacity equal to twice the capacity of capacitor I; and capacitor 3 has a capacity equal to three times the capacity of capacitor I. Capacitors 1, 2 and 3 are adapted to be connected to alternatingcurrent circuit 4 by means of circuit breakers 5, 6 and 1, respectively, which may be of any suitable type examples of which are well known to the art. As shown in the drawing, circuit breakers 5, 6 and I are of the well known latched-in type and are respectively provided with closing coils 8, 9 and I0 and trip coils H, l2 and I3.

In order to control the connections between capacitors I, 2 and} and" circuit 4 in response to a predetermined electric condition of circuit 4, which in the particular arrangement shown in the drawing is the voltage of circuit 4, I pro vide a contact-making voltmeter M which is connected to circuit 4. voltmeter I4 is arranged to effect the completion of an energizing circuit for a control rela I5, when the voltage of circuit 4 is below a predetermined value, and the completion of an energizing circuit for a control relay lfi, when the voltage of circuit 4 is above a predetermined value. When either control relay IE5 or 16 is energized, an energizing circuit is completed for a time relay H, which, after being energized for a predetermined time, initiates the operation of a suitable multiposition switch Hi to effect the necessary operations .of circuit breakers 5, 6 and l to change, in equal increments, the amount of capacity connected to circuit 4 until the voltage thereof is restored to its normal value. As shown in the drawing, multiposition switch I8 is a motor driven controller having a cylindrical drum l9 driven by a reversible motor 20 which is provided with an armature winding 21 and two field windings 22 and 23. When armature winding 2! and held winding 22 are simultaneously energized, motor 20 rotates in a direction to efiect a decrease in the amount of capacity connected to circuit 4. When armature winding 2| and field winding 23 aresimultaneously energized, motor 20 rotates in the opposite direction and efieots an increase in the amount of capacity connected to circuit 4. Cylindrical drum l9 carries contacts which respectively engage stationary contacts 24-42, inclusive, in various positions of the drum. As shown, drum H! has seven stopping positions respectively marked a,g, inclusive. In position a, circuits are completed by controller I8 to efiect the opening of circuit breakers 5, 6 and 1. In position b, circuits are completed to effect the closing of circuit breaker 5 and the opening of circuit breakers 6 and 1. In position 0, circuits are completed to efiect the closing of circuit breaker 6 and the opening of circuit breakers 5 and I. In position d, circuits are completed to effect the closing of circuit breaker l and the tion of closing coil 3.

opening or circuit breakers a and s. In position e, circuits are completed to efiect the closing of circuit breakers and i and the opening of circuit breaker 6. In position i, circuits are completed for efiecting the closing of circuit breakers 3 and 1 and the opening of circuit breaker 5. In P sition g, circuits are completed to efiect the closing of all of the circuit breakers.

Closing coil 3 of circuit breaker 5 has associated therewith two control relays 33 and as. An energizing circuit for control relay 33 is com pleted by controller 53 when it is in a position to effect the closing of the switch 5. Control relay when energized, completes a locking circuit for itself independently of 'the contacts of controller i3 and also an energizing circuit for the closing coil 3. As soon as switch 5 closes, an energizing circuit is completed for control relay 36 which completes a locking circuit for itself as long as controller 53 remains in a position to efiect the closing of switch 5. The energization of control relay 3% also interrupts the energizing circuit of control relay 33 so that it becomes deenergized and effects the deenergiza- In this manner closing coil 8 is energized only long enough to efiect the closing of circuit breaker 5 and cannot be reenergized thereafter until associated control relay 36 has been deenergized by the subsequent movement of controller 68 to a position in which it efiects the opening of circuit breaker 5.

Closing coil 3 of circuit breaker (5 has a similar pair of control relays 35 and "36 associated therewith and closing coil iii also has a similar pair of control relays 3? and 38 associated therewith.

In order to eiiect the desired equal changes in the capacity connected to circuit 9 in certaln of its positions, controller i3 has to open one of the circuit'breakers at substantially the same instant that another of the circuit breakers is closed. Sometimes the open circuit breaker is closed before the other circuit breaker is closed or vice versa. Also due, for example, to the contacts on drum i9 being out of alignment, there may be a suflicient overlap between the closing of one breaker and the opening of another breaker in certain positions of the drum to allow voltage relay l8 and its associated con:

trol relay 95 or it to operate and prevent motor 20 from moving drum i 9 far enough to effect the desired operation of the circuit breakers. In order to overcome this diificulty due to the sequential operation of the circuit breakers, I provide a time relay 39 which is so connected that, whenever the controller reaches a position in which it efiects the opening of one breaker and the closing of another breakerjrelay 39 maintains thecircuit of motor 20 completed for a suflicient length of time independently of the position of voltage relay H to insure that controller drum l9 moves far enough to effect the proper operation of the circuit breakers. In the particular arrangement shown in the drawing relay 39 is of the well known time delay dropout type, and an energizing circuit therefor is arranged to be completed by control relays 33, 35 and 31, respectively, whenever they are energized and also by a control relay 40 whenever it is energized. Relay 40 is arranged so that it is energized whenever circuit breaker 5 is closed and controller I8 is in a position to effect the opening of circuit breaker 5.

The operation of the arrangement shown in the drawing is as follows:

aaoaeee When circuit breakers 5, 6 and l are open and the voltage of circuit 4 decreases below a. predetermined value so that relay i4 completes an energizing circuit for control relay l5, an energizing circuit is completed for time relay I! through contacts 3! of relay i5- and contacts 52 of relay 39. If the voltage of circuit {2 remains below this predetermined value for a suficient length of time, relay i7 closes its contacts 93 and completes a locking circuit for relay 55 through its contacts 89. The closing of contacts :33 also completes an energizing circuit for controller motor 20 through armature winding 28, field winding 23, contacts M of relay 65, contacts 45 of relay i8, and contact 3i, segments and contact 26 of controller 88. Motor 263 then rotates in a direction to move drum W from its position it towards position b.

As drum i9 approaches its position b, an energizing circuit is completed for control relay 33 through contacts :36 of relay 3%! and contact 25, segments and contact 26 of controller M3.

The closing of contacts 97 of relay 33 completes a locking circuit for this relay which is independent of contacts 29 and 25 of controller it. By closing its contacts 38, relay 33 completes an energizing circuit for closing coil 8 to effect the closing of circuit breaker 5 so as to connect capacitor l across circuit i. By closing its contacts 99, relay 33 completes an energizing circuit for time relay 39.

When circuit breaker 5 closes its auxiliary contacts 59, an energizing circuit is completed for control relay 39 through contact 25, segments and contact 26 of controller it. By closing its contacts 5!, relay 3% completes a shunt circuit around contacts 58 of circuit breaker island by opening its contacts so, relay 39 interrupts the energizing circuit of relay 33 so that it becomes deenergized and interrupts the energizing circuits of closing coil 3 and time relay 39.

The energization of time relay 33, in response to the energization of relay 33, opens contacts 32 in the energizing circuit of time relay I? so that it becomes deenergized and at its contacts 63 interrupts the original energizing circuit of motor 2! and the locking circuit for relay i 5.

However, by closing its contacts 52, relay 33 completes another locking circuit for relay l5, and by closing its contacts 52 and 53, relay 33 maintains the circuit of armature winding 2! and field winding 23 completed until after circuit breaker 5 has closed and has effected the deenergization of relay 33 which, in turn, efi'ects the deenergization of time relay 39. Since relay 39 is of the time delay drop-out type, the circuit of motor 2| is maintained for a sufiicient length of time after circuit breaker 5 is closed to insure that controller 9 reaches its stopping position b.

If the increase in capacity efiected by the connection of capacitor I to circuit 4 does not restore the voltage thereof to normal so that volteffects the deenergization of conthe circuit of time relay I1 is resoon as time relay 33 closes its relay 40 associated with circuit breaker and control relay 35 associated with circuit breaker 6. The energizing circuit of control relay 40 includes auxiliary contacts 53 on circuit breaker 5 and contact 26, segments and contact 24 of controller I8. By closing its contacts 54, relay 46 connects trip coil II in parallel therewith so that circuit breaker 5 is opened to disconnect capacitor I from circuit 4. By closing its contacts 60, relay 40 completes an energizing circuit for relay 39.

The energizing circuit of control relay 35 includes contacts 55 of control relay 36 and contact 21, segments and contact 24 of controller I8. By closing its contacts 56, relay 35 completes an energizing circuit for closingcoil 9 to effect the closing of circuit breakeri so as to connect capacitor 2 across circuit 4. By closing its contacts 51, relay 35 completes a locking circuit for itself, and by closing its contacts 58, relay 35 completes an energizing circuit for time relay 39.

By closing its auxiliary contacts 59, circuit breaker 6 completes an energizing circuit for con trol relay 36 through contact 21, segments and contact 24 of controller I8. By closing its contacts 6|, relay 36 completes a locking circuit for itself, and by opening its contacts 55, relay 36 interrupts the energizing circuit of control relay 35 so that it becomes deenergized and opens the energizing circuit of'closing coil 9.

The energization of relay 39 maintains, in the manner heretofore described, the circuit of motor 20 completed for a sufficient length of time independently of the position of contact-making voltmeter I4 to insure that controller l8 reaches its stopping position c and thereby effects the opening of circuit breaker 5 and the closing of circuit breaker 6.

If the increase in capacity connected to circuit 4 to a value equal to twice the value of the capacity of capacitor I, which is effected by the closing -of circuit breaker 6 and the opening of circuit breaker 5, does not restore the voltage of circuit 4 to its normal value so that relay I5 is deenergized, the circuit of time relay I1 is again established through contacts 42 of relay 39 as soon as this relay becomes deenergized in response to the deenergization of relays 35 and 40. Time relay I1 then *completes, in the manner heretofore described, the energizing circuit of armature winding 2I and field winding 23 so that motor 20 moves the controller I8 out of its position c and towards its position d.

' As drum I9 approaches its position d. segments on the drum complete, through contacts 28 and 29, circuits to effect the energization of tip coil "I2 associated with circuit breaker 6 and control relay 31 associated with circuit breaker 1. The energizing circuit of tripcoil I2 includes auxiliary contacts 62 on circuit breaker 6 and contact 28, segments and contact 24 of contioller I8. The energization of trip coil I2 effects the opening of circuit breaker 6 to disconnect capacitor 2 from circuit 4.

The energizing circuit'of control relay 31 includes contacts 63 of relay 38 and contact 29,

segments and contact 24 of controller I8. By closing its contacts 64, relay 31 completes an energizing circuit for closing coil I0'to eifect the closing of circuit breaker 1 so as to connect capacitor 3 across circuit 4. By closing its contacts 65, relay 31 completes a locking circuit for itself, and by closing its contacts 66, relay 31 completes an energizing circuit of time relay 39.

By closing its auxiliary contacts 61, circuit breaker I II completes an energizing circuit for control relay 38 through contact 29, segments and contact 24 of controller I8. By closing its contacts 68, relay 36 completes a locking circuit for itself, and by opening its contacts 63, relay 38 interrupts the energizing circuit of control relay 31 so that it becomes deenergized and opens the energizing circuit of closing coil I0.

closing of circuit breaker 1 and the opening of circuit breaker 6, does not restore the voltage of v circuit 4 to its normal value, the circuit of time relay I1 is again established as soon as relay 39 recloses its contacts 42. Time relay I1 then completes, in the manner heretofore described, the

energizing circuit of armature winding 2I and field winding 23 so that motor 23 moves the con: troller I8 out of its position d and towards its position 2.

As drum I9 approaches its position 6, seg-' ments on the drum complete, through contact 25, the heretofore described circuit for control relay 33 to effect the closing of the circuit breaker 5, the deenergization of the time relay I1, and the energization and subsequent deenergization of the time relay 39 to insure that the controller I8 reaches its stopping position e.

Since circuit breaker 1 remains closed while controller I8 moves from its position (I to its position e, capacitors I and 3 are connected to circuit 4 as a result of the movement of the controller to its stopping position e. Control relays 33 and 34 and time relays I1 and I9 are controlled in the same manner as heretofore described in connection with the movement of the controller from its position a to its position b.

If the increase in capacity connected to circuit 4 to a value equal to four times the capacity of capacitor I, effected by the simultaneous connection of capacitors I and 3 to circuit 4, does not restore the voltage thereof to normal, the circuit of motor 28 is again completed by relay H a predetermined time after the controller reaches position 6 so that the controller moves towards its position f. As the controller approaches its position f, circuits are completed, through contacts 26 and 21, to effect the opening of circuit breaker 5 and the closing of circuit breaker 6 in the same manner as when the controller moves its position b to its position 0'. Since circuit breaker 1 remains closed while the controller moves from its position e to its position I, capacitors 2-and 3 are connected to circuit 4 as a result of the movement of the controller to its stopping position I.

If the increase in capacity connected to circuit 4 to a value equal to five times the capacity of capacitor I, effected by the simultaneous connection of capacitors 2 and 3 to circuit 4, does not restore the voltage thereof to normal, the circuit of motor 20 is again completed by relay I1 a predetermined time after stopping position f is reached so that the controller moves towards its position 9. As the controller approaches its position 9, a circuit is completed, through contact 25, to effect the closing of circuit breaker in the same manner as when the controller moves from its position a to its position b. Since circuit breakers B and I remain closed while the controller moves from its position I to its position g, capacitors l, 2 and 3 are connected to circuit 4 as a result of the movement of the controller to its position I so that the capacity connected to circuit 4 is increased to a value equal to six times the capacity of capacitor I. In position I of controller [8, the circuit, through its contact 3|, is opened so that further movement of the controller is prevented in a direction which eifects an increase in the amount of capacity connected to circuit 4.

If, while controller I8 is in its position a and capacitors I, 2-and 3 are connected to circuit 4, the voltage of the circuit 4 exceeds a predetermined value, voltmeter |4 completes an energizing circuit for control relay l6 which, in turn, completes, through its contacts and contacts 42 of relay 39, an energizing circuit for time relay l1. After being energized fora predetermined time, relay I I closes its contacts 43 and completes a locking circuit for relay it through its contacts 8!. The closing of contacts 43 also completes an energizing circuit for motor 28 through armature winding 2|, field winding 22, contacts H of relay l6, contacts 12 of relay [5 and segment 32. Motor 20 then rotates in a direction to move drum l9 from its position gto its position I.

As the drum approaches its position f, a circuit is completed, through contact 26, for control relay do to effect the opening of circuit breaker 5 in the same manner as when the controller moves from its position b to its position 0. Control relay 46 also controls time relays H and 39, in' the same manner as heretofore described, to insure that the controller reaches its stopping position in case the voltage of circuit 4 is restored to normal before the controller reaches that position.

If the decrease in the capacity connected to circuit 4 to a value equal to five times the capacity of capacitor I, efiected by the disconnection of the capacitor i from circuit l, does not restore the voltage of circuit 4 to normal, the circuit of motor 20 is again completed by relays i6 and if a predetermined time after stopping 3 are connected to circuit 4 as a result of the movement of the controller to its position 6. Ihe energization of control relay 3%, during the closing operation of circuit breaker 5, controls time relays I? and 39, in the same manner as heretofore described, to insure that the controller reaches its stopping position e 'in case the voltage of circuit 4 is restored to normal before the controller reaches position e.

If the decrease in the capacity connected to circuit 4 to a value equal to four times the capacity of capacitor i, effected by the movement of the controller to position e, does not restore the voltage of circuit 4 to normal, the circuit of motor 20 is again completed by relays l6 and I! a predetermined time after stopping position e is reached so that the controller moves towards its position d.

As the controller approaches its position d, a circuit is completed, through contact 26, to eifect the opening of circuit breaker 5 in a manner heretofore described. Since circuit breaker I remains closed while the controller moves from its position e to its position d, capacitor 3 is connected to circuit 4 when position d is reached.

If the decrease in the capacity connected to circuit 4 to a value equal to three times the capacity of capacitor I, effected by the movement of the controller toposition d, does not restore the voltage of' circuit 4 to normal, the circuit of motor 20 is again completed by relays IS and I! a predetermined time after stopping position (1 is reached so that the controller moves towards its position 0.

As the controller approaches its position 0, a circuit is completed, through contact 21, to effect the closing of circuit breaker 6 in a manner heretofore described. Also a circuit is completed for trip coil l3 through contacts I4 of circuit breaker l, and contact 30, segments and contact 24 of controller l8; The energization of trip coil i3 eflects the opening of circuit breaker i so that capacitor 3 is disconnected from circuit 4. Therefore, as a result of the controller moving from position it to position c, capacitor 3 is disconnected from circuit 4 and capacitor 2 is reconnected to circuit 4 so that the capacity connected to circuit 4 is reduced to a value equal to twice the capacity of capacitor I.

If the voltage of circuit 4 is not restored to normal by the reconnection of capacitor, 2 thereto, the circuit, of motor 20 is again completed by relays IE and ll'a predetermined time after position 0 is reached so that the controller movestowards proaches its position b, circuits are completed, through contacts 25 and 26, to effect, in the manner heretofore described, the closing of circuit breaker 5 and the opening of circuit breaker 6 so that capacitor 2 is disconnected from circuit 4 and capacitor l is reconnected to circuit 4, so that the capacity connected to circuit 4 is reduced to the capacity of capacitor i. If the voltage ofcircuit 4 is not restored to normal as a result of the movement of the controller to its position b, the circuit of motor 2|] is again completed by relays l6 and IT a predetermined time after position b is reached so that the controller moves towards its position a. As the controller approaches its position a, a circuit, is completed, through contact 26, to eifect the opening of circuit breaker 5, in the manner heretofore described, so that capacitor I is disconnected from circuit 4. Since in position a the circuit, through contact 32 of controller I8, is open, further movement of the controller is prevented in a, direction which 'eifects a decrease in the amount of capacity connected to circuit 4.

While I have, in accordance with the patent statutes, shown and described my invention as applied to a particular system and as embodying various devices diagrammatically indicated,

changes and modifications will be obvious to those skilled in the art, and I therefore aim in the. appended claims to cover all such changes position b. As the controller apand modification as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by- 1' Letters Patent of the United States is:

1. In combination, an electric circuit, a plurality of reactance devices, individual switching means controllmg the connection between each device and said circuit, a multiposition switch, means controlled by the position of said switch for eiIecting predetermined operations of said switching means, means responsive to a predeto the operation of said switching means operatermined electric condition of said circuit for I effecting the movement of said switch through its various positions; and means responsive to the operation of said switching means for continuing independently of said electric condition the movement of said switch for a predetermined time afer said switch has effected a predetermined operation of said switching means.

2. In combination, an electric circuit, a plurality of reactance devices, individual switching means controlling the connection between each device and said circuit, a multiposition switch,

means controlled by the position of said switch for efiecting the substantially simultaneous opening and closing of different switching means,

" means responsive to a predetermined electric condition of said circuit for effecting the movement of said switch from one position to another, and means responsive to the operation of said switching means for continuing independently of said electric condition the movement of said switch for a predetermined time after said switch has effected the closing of certain of said switching means.

3. In combination, an electric circuit, a plurality of reactance devices, individual switching means controlling theconnection between each device and said circuit, a multiposition switch, means controlled by the position of said switch for eflecting the substantially simultaneous opening and closing of difierent switching means, means responsive to a predetermined electric condition of said circuit for effecting the movement of said switch from one position to another,

tive to continue independently of said electric condition the rotation of said motor in the direction it is rotating for a predetermined time after said switch has effected predetermined operations of said switching means.

5. In combination, an electric circuit, a plurality of reactance devices respectively having reactances which difier in an arithmetical progression, individual switching means controlling the connection between each device and said circuit, a reversible motor driven multiposition switch, means controlled by said switch for eiIecting the opening and closing of said switching means in a predetermined sequence when said motor rotates in one direction and in the reverse sequence when said motor rotates in the opposite direction, means responsive to a predetermined electric condition of said circuit for effecting the rotation of said motor, and timing means responsive to the operation of said switching means operative to continue independently of said electric condition the rotation of said motor in the direction it is rotating for a predetermined time after said switch has effected the closing of any of said switching means and the opening of certain of said switching means.

6. In combination, an electric circuit, a plurality of reactance devices connected to said cirand means responsive to the operation of said switching means for continuing independently of said electric condition the movement or said switch for a predetermined time after said switch has eflected the opening of certain of said switching means.

4. In combination, an electric circuit, a plurality of reactance devices respectively having reactances which differ in an arithmetical progres- 1 sion, individual switching means controlling the connection between each device and said circuit,

a reversible motor driven multiposition switch, I

cuit, said devices respectively having reactances which differ in an arithmetical progression, individual switching means controlling the connections between each device and said circuit, a multiposition switch, means responsive to the movement of said switch for efl'ecting the operation of said switching means so as to vary the amount of reactance connected to said circuit in increments equal to the reactance of the device having the smallest reactance, means responsive to a predetermined electric condition of said circuit for effecting the movement of said switch from one position to another, and'means responsive to the operation of said switching means for continuing independently of said electric condition the movement of said switch for a predetermined time after said switch has effected predetermined operations of said switching means.

ARVID E. ANDERSON. 

